American Institute of Timber Construction (AITC) - Timber Construction Manual

This book is printed on acid-free paper.

Copyright 2012 by American Institute of Timber Construction. All rights reserved.

Published by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600, or on the web at www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at www.wiley.com/go/permissions.

Limit of Liability/Disclaimer of Warranty: While the publisher and the author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor the author shall be liable for damages arising herefrom.

For general information about our other products and services, please contact our Customer Care Department within the United States at (800) 762-2974, outside the United States at (317) 572-3993 or fax (317) 572-4002.

Wiley publishes in a variety of print and electronic formats and by print-on-demand. Some material included with standard print versions of this book may not be included in e-books or in print-on-demand. If this book refers to media such as a CD or DVD that are not included in the version you purchased, you may download this material at http://booksupport.wiley.com. For more information about Wiley products, visit www.wiley.com.

Library of Congress Cataloging-in-Publication Data:

Timber construction manual / American Institute of Timber Construction.Sixth edition.

pages cm

Includes index.

ISBN 978-0-470-54509-6 (hardback); 978-1-118-27961-8 (ebk.); 978-1-118-27964-9 (ebk.); 978-1-118-27965-6 (ebk.); 978-1-118-27966-3 (ebk.); 978-1-118-27968-7 (ebk.); 978-1-118-27973-1 (ebk.)

1. Building, WoodenHandbooks, manuals, etc. I. American Institute of Timber Construction.

TA666.T47 2012

694dc23

Preface

The American Institute of Timber Construction (AITC) has developed this Timber Construction Manual for convenient reference by architects, engineers, contractors, teachers, the laminating and fabricating industry, and all others having a need for reliable, up-to-date technical data and recommendations on engineered timber construction. The information and the recommendations herein are based on the most reliable technical data available and reflect the commercial practices found to be most practical. Their application results in structurally sound construction.

The American Institute of Timber Construction, established in 1952, is a nonprofit industry association for the structural glued laminated timber industry. Its members design, manufacture, fabricate, assemble, and erect structural timber systems utilizing both sawn and structural glued laminated timber components. These systems are used in homes; schools; churches; commercial and industrial buildings; and for other structures such as bridges, towers, and marine installations. Institute membership also includes engineers, architects, building officials, and associates from other industries related to timber construction.

The first edition of the Timber Construction Manual was published in 1966. Changes in the wood products industry, technological advances, and improvements in the structural timber fabricating industry necessitated revisions of the Manual. New lumber sizes and revisions in grading requirements for lumber and glued laminated timber were reflected in the second edition published in 1974. The third edition was published in 1985 to reflect new information on timber design methods. The fourth edition of the Manual was published in 1994 and contained updated design procedures used for timber construction. The fifth edition (2005) added sections on timber rivet fasteners and load and resistance factor design.

This sixth edition represents a major revision of the format of the Timber Construction Manual. Chapters have been completely restructured for more logical and complete presentation of information. Long chapters have been divided into smaller chapters for improved readability and reference.

The sixth edition has also been expanded with completely new chapters on glulam arches, LRFD bridge design, fire safety, and moment splices. More than 30 new design examples have been added, including an appendix entirely composed of design examples.

Preparation of the Timber Construction Manual was guided by the AITC Technical Advisory Committee and was carried out by AITC staff, the engineers and technical representatives of AITC member firms, and private consultants. Suggestions for the improvement of this manual will be welcomed and will receive consideration in the preparation of future editions.

Although the information herein has been prepared in accordance with recognized engineering principles and is based on the most accurate and reliable technical data available, it should not be used or relied on for any general or specific application without competent professional examination and verification of their accuracy, suitability, and applicability by a licensed professional engineer, designer, or architect. By the publication of this manual, AITC intends no representation or warranty, expressed or implied, that the information contained herein is suitable for any general or specific use or is free from infringement of any patent or copyright. Any user of this information assumes all risk and liability arising from such use.

Chapter 1

Timber Construction

The American Institute of Timber Construction (AITC) has developed this Timber Construction Manual to provide up-to-date technical information and recommendations on engineered timber construction. Topics of the first chapter include materials, structural systems, economy, permanence, seasoning, handling, storage, and erection. With an understanding of these topics, the designer can more effectively utilize the advantages of wood construction. Specific design information and recommendations are covered in subsequent chapters, with accompanying design examples. Supplementary information is provided in appendices.

This manual applies primarily to two types of wood materialssawn lumber and structural glued laminated timber (glulam). Sawn lumber is the product of lumber mills and is produced from many species. Glued laminated timbers are produced in laminating plants by adhesively bonding dry lumber, normally of 2-in. or 1-in. nominal thickness, under controlled conditions of temperature and pressure. Members with a wide variety of sizes, shapes, and lengths can be produced having superior strength, stiffness, and appearance. In addition, heavy timber decking, structural panels, and round timbers are also discussed.